Efficacy and safety of Tanreqing injection for cough caused by acute trachea-bronchitis disease: A systematic review and meta-analysis of randomized controlled trials

Ethnopharmacological relevance: Tanreqing injection (TRQI) is an intravenous herbal preparation derived from 5 types of traditional Chinese medicines including Scutellariae Radix, Lonicerae Japonicae Flos, Forsythiae Fructus, bear bile powder and goral horn, incorporating baicalin, chlorogenic acid, ursodeoxycholic acid, and goose deoxycholic acid and other compounds known for anti-inflammatory properties, is widely used in China to treat cough caused by acute trachea-bronchitis disease (ATB). Aim of the study: To investigate the clinical efficacy and safety of Tanreqing injection (TRQI) with and without Western medicine (WM) for cough caused by acute trachea-bronchitis (ATB). Materials and methods: We systematically searched eight databases, including CENTRAL, Embase, PubMed, Science Direct, Wiley, China National Knowledge Infrastructure, Chinese Biomedical Literature Database and WanFang, from inception to August 2023 for randomized clinical trials (RCTs) on TRQI for cough caused by ATB. The critical outcomes of interest were time to symptom disappearance, including time for cough symptom to disappear and time to improve cough and sputum production. Important outcomes included symptom disappearance rate, adverse events (AEs) and lung function. We carried out random-effects meta-analysis using Review Manager 5.4 and assessed the certainty of evidence utilizing the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Results: A total of 2872 citations were identified by our search, of which 26 eligible RCTs enrolled 2731 participants. Low to moderate certainty evidence showed that when compared with WM, TRQI plus WM treatment was associated with a favorable effect on the time for cough symptom to disappear (MD-2.21 d, 95% CI-2.64 to-1.78), time to improve cough and sputum production (MD-0.68 d, 95% CI-0.83 to-0.53), symptom disappearance rate (RR 1.37, 95% CI 1.20 to 1.55), forced vital capacity, and forced expiratory volume in 1 s (MD 0.38 L, 95% CI 0.26 to 0.50; MD 2.92%, 95% CI 1.29 to 4.56, respectively). In terms of AEs, there was no association between TRQI plus WM and WM (RR 0.55, 95% CI 0.14 to 2.21; low-certainty evidence). Very low certainty evidence showed that TRQI alone was associated with reduced time to improve cough and sputum (MD-0.14 d, 95% CI-0.26 to-0.02) and increased symptom disappearance rate (RR 1.89, 95% CI 1.24 to 2.88; low certainty evidence) compared to WM.